Duplicate WordPress Site on Same Server

I am working on a WordPress site for a company. Recently the admin from the company cannot log into the Dashboard – when going to this URL ‘domainname.ie/wp-admin’ it gets redirected to this ‘domainname.ie/wp-login.php?redirect_to=http%3A%2F%2Fdomainname.ie%2Fwp-admin%2F&reauth=1’.

I have searched for answers on this and the most common reply was to either rename the plug-ins folder or uninstall plug-ins and reinstall to see which one is causing this issue.

Point to note is that the website is working fine, just the login url is broken

So what I am trying to do is create a duplicate version of the site in a subfolder to test any possible solutions without affecting the live site.

So far I have taken down a copy of all the WordPress files from the server, created a new database and imported a copy of the live site database to the new database (I don’t have access to phpMyAdmin so I talked through it over the phone with the company’s IT guy).

I have read through this – http://codex.wordpress.org/Moving_WordPress and I am just wondering if these steps will be the same for creating a duplicate copy of the site. Where it says edit the WordPress address and Site Address in the control panel – will I have to do this in phpMyAdmin before I can upload files and get the duplicate version up and running.